Recognition of myocardial injury after non-cardiac surgery is difficult, since strong analgesics (e.g. opioids) can mask anginal symptoms, and ECG abnormalities are subtle or transient. Thorough knowledge of the pathophysiological mechanisms is therefore essential. These mechanisms can be subdivided into four groups: type I myocardial infraction (MI), type II MI, non-ischaemic cardiac pathology, and non-cardiac pathology. The incidence of type I MI in patients with a clinical suspicion of perioperative acute coronary syndrome (ACS) is 45-57 %. This percentage is higher in patients with a high likelihood of MI such as patients with ST-elevation ACS. Of note, the generalisability of this statement is limited due to significant study limitations. Non-ischaemic cardiac pathology and non-cardiac pathology should not be overlooked as a cause of perioperative myocardial injury (PMI). Especially pulmonary embolism and dysrhythmias are a common phenomenon, and may convey important prognostic value. Implementation of routine postoperative troponin assessment and accessible use of minimally invasive imaging should be considered to provide adequate individualised therapy. Also, addition of preoperative imaging may improve the stratification of high-risk patients who may benefit from preoperative or perioperative interventions.
Int Heart J. 2016 May 25;57(3):278-84. doi: 10.1536/ihj.15-352. Epub 2016 Apr 28.
Individuals with intermediate to high cardiac risk for major noncardiac surgery suffer from perioperative myocardial ischemic injury. The purpose of this study was to evaluate the long-term impact of postoperative cardiac troponin elevation on clinical outcome after major noncardiac surgery.Patients (n = 750) aged ≥ 50 years who underwent major noncardiac surgery were eligible for the study. Postoperative cardiac troponin-I data were collected retrospectively and consecutively. The primary outcome measure was allcause mortality. The median follow-up period was 1727 days in all patients.Among 750 patients, 92 (12.2%) showed elevated postoperative troponin-I above 0.10 ng/mL. Operative mortality was 4.1% (31 subjects), and patients with troponin-I elevation showed a higher operative mortality rate (RR: 4.23, 95% CI: 2.67-11.31, P < 0.001). In multivariate Cox regression analysis, a troponin-I concentration above 0.10 ng/mL was associated with all-cause mortality (RR: 1.73, 95% CI: 1.27-2.36, P < 0.001). It should be noted that there was a significant difference between patients with elevated and non-elevated troponin-I in the rate of mortality until 6 months. However, these differences disappeared after 6 months.An elevated troponin-I level conferred an increase in mortality during the 7 year follow-up period after major noncardiac surgery. This difference in mortality was mainly derived from the result within the first 6 months.